Automatic transmission



E. J. FARKAS AUTOMATIC TRANSMISSION 4 Sheets-Sheet 1 Nov. 7, 14950 FiledAug. 22, `1945 www QNI.

INVENTOR.

v//ft NOV- 7, 1950 E. J. FARKAS 'AUTOMATIC TRANSMISSION 4 Sheets-Sheet 2Filed Aug. 22, 1945 1NVENTOR uw c @6K Nov. 7, 1950 E, JJFARKAS 2,528,584

AUTOHATIC TRANSMISSION Filed Aug. 22, 1945 4 Sheets-Sheet 5 fig. I 'JZ'.9

Iliff/fha., By INI/MOR. am o. Mg@

Nov. 7, 1950 K E. J. FARKAs 2,528,584-

Aurolmrc TRANSMISSION Filed Aug. 22, 1945 4 Sheets-Sheet 4 al@ A ,ll

INVENTOR.,

Patented Nov. 7, 1950 2.52:;,534 AUTOMATIC 'raaNsmssmN Eugene J. Farkas,Detroit, Mich., aasignor to Ford Motor Company, Dearborn, Mich., a cornoration of Delaware Application August 22, 1945, Serial No. 61I.,975

This invention relates to a.v transmission; and, more particularly, tothat type of transmission in which mechanical and iluid powertransmitting means are combined and automatically operated to obtainmaixmum eiilciency and smoothness in torque conversion in motorvehicles.

An object oi this invention is to provide a mechanical power path forthe higher forward speeds, while incorporating a. iluid power element inthe low and reverse speeds. Another object is to apply completeautomatic operating means to a transmission of the combined hy- ,draulicplanetary gear type to obtainv smooth transition between the successivestages oi' operation. Still another object is to devisean automatic,hydraulically operated control 'means particularly applicable to suchtransmissions and forming an internally disposed part thereof and whichis inherently so flexible and responsive in operation that thetransition between stagesvwill be effected quietly and smoothly whetherthe vehicle speed is increasing or decreasing and which will effect theprecise operation called for under the particular circumstances.

One of the principal advantages of the present construction is that theoperation of the hydraulic coupling is limited to the lower speeds atwhich the coupler elciency is not too important a factor and that in theupper ranges the drive is directly through a more or less conventionalmechanical transmission. It follows from this that automatic means areprovided to render the hydraulic coupling inoperative under advancedspeed conditions and to return it to operation when the speed decreasesto a point at which such operation is again feasible. These operationsare conducted automatically by the control mechanism itself and thiscontrol mechanism requires no exterior control during either advancingor declining speeds to be completely effective. Indeed, the only manualcontrol required is the selection of the direction of opery zo claims.(ci. 'i4-u2) 2 deed, is actually `.nterchangeable with the present slidegear tra] ismissions used in conventional practice.

t Due to the spe( lilc operating or control means relied upon, thi`shifting between successive stages is comple aely automatic andextremely smooth. This is true whether the transitions are taking placethrough increasing or decreasing speeds. Furi her, the operation is soilexible that the transmission will respond readily to any demandsplaced lpon it in ordinaryv driving and, thus, the vehicle respondsinstantly to demands for increased speed and will readapt itself toordinary operating conditions when these extreme demands a re met. Inaddition, the driv- Fina] ly, automatically operable anti-' Y creepingmeans im incorporated to obviate a very dangerous. condition met with inthe majority ot fluid-coupled slrives.

With these ani other considerations in view, the invention con sists ofthe apparatus described in this speciilcaton, claimed in the claimsandillustrated in tl e accompanying drawings, in which:

Figure 1 is a lol lgitudinal vertical section taken throughfthe tran:mission of this invention. I Figure 2fis a transverse vertical section`taken as indicated on tl le line 2-2 of Figure 1.`

Figure 2A lis n corresponding view taken as molested by the unam- 2A ofFigure 1.

, Figures 3, 6 an d 8 are longitudinal views, on a greatly enlargedscale, of a portion of the, apparatus shown on Elgure 1, and morespecifically illustrating the o `eration of the hydraulic clutchoperating meansv for First and. Reverse, Second and Third speed: 1,respectively.

Figures 4, 5, 7 and 9 are schematic drawings of the transmis: lonshowing the power transmission through the mechanism for First, Re-

verse, Second ard Third speeds, respectively.

Figure lois a transverse section of the view taken as indicate i by theline lil-I0 of Figure l. Figuresll to i6 are transverse sections takenthrough the clutch operating means at various section lines to :how thehydraulic connections existing at successive stages'.4 corresponding 4tothose shown in li lgures 3, 6 and 8. 4

Referring to F gure l, the reference character Ii indicates generally atransmission having a housing I2, with a forward flange Il through whichit may be attached to an engine and an 3 universal joint housing Il atits rear end-to accommodate the connection to the rear axle drive meansof any of the usual types. At the forward end. the flywheel Il is boltedand doweled to engine crankshaft Il and the starter ring gear l1 ismounted in the usual manner. Also. secured to the rear face of theflywheel il adjacent its periphery is the impeller housing I8 of aFottinger type iluid coupling I8. Radialiy spaced vanes 2| aremounted inthe housing i8 and cooperating vanes 22 are secured on the runnerhousing 23. This-last housing is mounted on a hub 2l which is journaledthrough an overrunning clutch 25 on the main shaft extension 28. havingits forward end piloted in the flywheel at 21 and splined at 88 at itsrear end to the main shaft It; The' particular overrunning clutch-`shown as IB is more fully described in a copending application illedherewith, entitled "Overrunning Clutch, Serial No. 611,914, in the namesof Eugene J. Farkas and Joseph W. Rackle. It suffices here to note thatit includes a race 8l having spaced rims 82 joined byseparators 8l.carrying sprags 3l. These are urged into driving engagement between theinner surface of the hub 24 and the outer concentric surface of theshaft extension 2B by a simple single coil spring received in thenotches 85;

A sleeve 86 is rotatably mountedon the main shaft 28 and externally`iournaled by a bearing 81 in the forward flange il. The central hub -88of the housing I8 is piloted on the intermediate portion of the sleeve86, and an oil seal 88 is interposed between the central portion of theflange Il and the external surface of the central hub 88. The impellerhousing I8 is drivingly connected to the forward end of the sleeve 80through a a cushioned clutch plate vconstruction of conventional designof which the driven hub 4| is splined at l! to the sleeve 38, and thedriving plates 48 carry a cushion spring 44 and a driving pin I5. Thesleeve 36 terminates rearwardly in a splined drum I6 of enlargeddiameter, carrying a series of clutch driving discs 41 (this clutchmechanism referred to generally is the second speed clutch 4I), as wellas that of the third speed clutch 5 8 later described, are shown indetail only in the upper half of Figure 1, to avoid unnecessary duplication). 1-

Continuing rearwardly along the main shaft 29, the principal clutchassembly is shown (the operating portion of this assembly is shown inmuch enlarged scale in Figures 3, 6, and 8).

Essentially, the -assembly consists of an inner clutch sleeve 49rotatably mounted on the main shaft 28, an intermediate concentricallyarranged longitudinally slidable sleeve valve 5I and the outerconcentrically arranged clutch carrier or power transmitting member 82splined at I3 to the rearward extension Il of the clutch sleeve 48. Thesleeve valve 5| is normally urged rearwardly by two coil springs bearingagainst the retainer ring 55 cooperating with the longitudinal thrustbearing I6; The primary spring l1 is alone operative on the sleeve valveduring the initial stages of its travel, while the secondary spring Ilalso cornes into operation during the remainder of its travel. It willbe noted that there are several co-operaiing ports in the clutch carrierl2, sleeve valve 5i and clutch sleeve il. The description of theirlocation and function, and of the operation of the springs referred toabove will be deferred until later in this specification where theoperation'of the device is considered in detail. It will be sumcient tonote here that two circumferential chambers separated by the ring 8| areformed between the clutch sleeve I8 and the main shaft II and these ared as the second speed clutch supply l0 and third speed clutch supply 88.respectively. A second speed oil duct 82 leads rearwardly through themain shaft 28 to a central cavity I3 in the main driven shaft M. Thecavity il. in turn. communicates through the lead 8l with the secondspeed delivery port 88 of the oil pressure pump I1. On the other hand,the third speed clutch supply Il communicates through the .third speedoil duct 08 and the radial lead B8 with a bore 1I at the rear end of themain shaft 28. 'I'he rear end of the duct il and the outer end of thelead 8l are A closedby plugs 12. The bore 1l is connected by `ablelength and a disc-like body 18 in which are formed a number (in thiscase twelve) of opposed clutch operating cylinders designated as 18 forthe second speed clutch l0, and V88 for the third speed clutch 50. Thecarrier proper is completed by a forward shell 8| and a rearward 'shell82 mounted on the periphery of the body 18 and all three elements aresecured together by the bolts 88. The shells 8i and 82 have inwardlyextending flanges 8l and 85, respectively, which'serve as abutments forthe clutch discs. operating pistons are mounted in each of the cylinders19 or 80 on both sides of the body 1'8and are responsive to oil pressuresuppliedthrough` -leads extending through the clutch hub 11, the exactlocation and operation of these being described later. 'Ihe clutchoperating rings 88 and 88 forsecond and third speeds, respectively,V aremounted forwardly and rearwardly of the body 18, respectively, and haveextensions 82 engaging the several pistons 86. vA plurality of clutchdriven discs 93 having a dished shape are inter.

leaved with the clutch driving discs l1 and-are restrained from rotationrelative the clutch carrier 52 by the bolts 88. A coil spring 8lnormally urges the clutch operating ringf! toward the carrier body 18disengaging the discs 8l and l1. A brake drum 85 is formed on theexternal surface of the rearward shell 82 and co-operates with thereverse brake band 86, received in the recess 81 in the housing I2.These brakes (see Figure 2) are of the form shown generally in Patent2,020,404, comprising a pair of metal bands of rectangular cross sectionhaving several wraps around the drum. The adjacent inner ends have eyesand are anchored by longitudinal anchor pim 81 in the anchor housings88. The outer ends carry the lugs Ill through which the bands areoperated.

Continuing rearwardly, the main driven shaft M is piloted at its forwardend on the bearing 88 on the rear end of the main shaft 28. Thisparticular section of the housing encloses the planetary gearing systemcomprising a planet carrier 99; the sun pinions ill (formed on therearward extension Il of the clutch sleeve'll), |82 (formed integrallywith the main shaft 29) and |88 (formed on the forward end of the main:Irl n shaft 8l); and three 'sets of planet pinion u and |88,rotatably'mounted in the planet carrier 80 and in constant mesh withtheir respective sun rs each comprising three pinons I, "l

piniona. 'me carrier 55 has a spiined clutch drum |51 extendingforwardly therefrom within the clutch carrier 52 and carrying a numberof clutch driven discs 55 which cooperate with a number oi' clutchdriving discs y|55 `secured to the carrier 52. lhis clutch. :designatedas the third speed clutch 55, is operated, asy was the secondspeedclutch III, through the pistons 55 in the cylinders 55, the `clutchoperating ring 55, and the spring. l

'l'he planetary clusters referred' to above are rotatably moimted onthehollow shafts ||I secured in the carrier 55. The planet pinion `|II runsthe entire lengthof the cluster and the other two planet pinions |55 and|55 are keyed to it and held in position by the retainer ||2, thusgiving a substantially integral construction. The carrier 55 is made intwo parts, cut transversely of the principal axis and welded together at||5 on the struts Ill.y It extends rearwardly to form the inner race ||5supporting the forward speeds overrunning clutch ||5, whose outer race||1 is a part of the forward speeds brake drum ||5. Thebrake band ||5 inthe recess |2| and the overrunning clutch I|5 are selectively operableto prevent reverse. movement of the carrier 55. Apump housing |22 issecured to the rear end of thehousing i2 andsupports the main drivenshaft 55 in the bearing |25. The pump housing |22 encloses an impellerhaving an outer driven member |25 and an inner driving memberfl25,

together with the suction intake |25 and the delivery chamber |21. 'Ihepump housing is completed by'the cover. plate |25, which also supports4the universal joint housing I5.

Reference is nowmade to the lower portion of Figure i in which themanually operated control is shown. -This comprises a rock shaft |25Journaled on the housing I2 at |3| having an operating arm |52 at itsforward end connected through operating linkage |55 (not shown indetail. but including connections leading to an opk ei'ating` leverpreferably placed adjacent the steering wheel of the vehicle in whichthe transmission is installed), two brake operating cams |55 and |55ianda ratchet control |55. Figures 2 and 2A show the precise structuralrelations oi' these elements. In Figure 2. the reverse brake operatingcam III is shown inthe position ocwpied in reverse operation, duringwhich the band 55 engages the drum 55; but adapted. on lrota-` tioncounterclockwise, to engage the roller |45 on the yliivoted arm |55.This arm also has a cam surface |41 bearing against the lug |55 on theband 55. The arm |55` is urged inwardly by a spring |55 tending toengage the brake: but the spring housing |5| includes an hydraulicchamber |52, `which is connected through the duct |55 directly to thedelivery chamber |21 of the oil pressure pump 51 A piston |55 is mountedin the cylinder |52 and has a connecting rod |55 to which is attachedthe spring retainer |55. 'Ihe rod |55 has a hollow stem |51 and bleeds|55 through which fluid leaking behind the piston |54 may drain to the-interlor of the housing. `'l'he purpose of this construction is toprevent engagement `of reverse while the vehicle is moving forsaam . staecnuinber ma uneavirmwumultimania` Y55 cannot be engage d evenifthecam |55 is moved to the position shcwn in Figure 2. Before the reversedrive can be instituted, the forward movement of the vehiclel must bestopped.

Figure 2A shows the operating mechanism fory the forward speed: brakelil, which again inf. cludes a cam |55 shown in the positionoocupied inforwardoperatic n during `which the band ||5 engages the drum III; butadaptedmn clockwise rotation, to engage the roller `|5| on the pivoted`|55 to release he brake. The arm is loaded` by the spring |55 rnd has acam surface |55 at its upper extremity engaging thelugs illweided totheouter ends ci the band H5. The ratchet |55 is shown in the same view(of course, in forward speed position) and co-operates with thespring-loaded selector |52 by which the shaft |25 may also be se :uredin either the reverse or neutral notches |45 and |55. While elements|55iand |55 have b een described in the singular,

each (aswill be a1 parent from Figure l) coni-` prises two separat: armsstraddle mounted `to by the pipe |55 lfading to thesuction intake |25and delivers it under pressure to the cham,-

,A pressure reliefvalve I5| rmounted` ber |21. in one side of thehousing |22, comprises a plunger |52 normolly urged upwardly by thespring |55. When the oil pressure in the delivery chamberl |21 re achesa predetermined maximum, the plunger |52 is depressedypermitting flowfrom the char iber |21 directly to the suction side |25 of the pump, Thehousing |22 also includes an accelerating valve |55, having a plunger|55 norma ly urged `downwardly by the spring |55. The lower end of theplunger |55 engages an eccentric cam |51 on the control rod |55. Twocontrol a rms |55 and |15 are rotatably mounted on the control rod |55and are connected to the foot a :celerator controland a manualaccelerator control, respectively. Aflnger |12 is pinned to the controlrod |55 and is so ar. ranged that indepei dent movement of either arm|55 or |15 will be transmitted to the cam |51. 'I'he plunger |55 has asection |15 of reduced diameter intermediat e its ends and in theplunger's lowermost position, the section |15 communicates with` ametering bleed |15, whose function will be` described later, opening tothe transmission housing. The ultli nate range of travel of the plunger|55 is regu] ated by the bolt |15 engaging the upper and low erboundaries of this section In ordinary opere tion at third speed, oilunder pressure to operati the second speed clutch is delivered from theielivery chamber |21 through the second speed de livery port 55 and thelead 5l (see Figure l). Ol for operation of the third speed clutchpasse: through the lead |15 from chamber |21 to the section |15 andthence through the ofl'set ead |11 (indicated in dotted line in Figure10) whose longitudinal position corresponds with tie circumferentialchannel 15 on the main driver shaft 55, the radial lead 15` and thesleeve 15. When an immediate acceleration is desired neces sitating theuse of the second speed gear ratio, th e acceleration valve |55 may beoperated automatically through the completedepression or the acceleratorpedal: or the transmission may be kept in the second speed ratio througha manual control: Ain either case, the plunger |85 is raised inresponseto the' resultant rotation oi' the eccentric cam |81. This will'shut o!!the communication between the lead |18'to the section |18, therebyreducing the pressure in the third speed clutch supply. Thisvaction isieffective 'only when the control (whether pedal or manual) issubstantially completely vdepressed inre'sponse to the demand forincreased speed.`

engagement despite the fact that'the pump may no longer be supplyingiluid to them. This will be explained more i'ully when ther operation ofthe control device is. considered indetail.-

Reference isrnow made to the central portion of Figure 1 and the lowerpart oi' vFig-ure 2. It will be noted'that centrifugally operatedweights |18 are arranged between each of the pairs oi cylinders 19 or88, and are pivoted at |18 on the carrier 52. Each weight has a crankarm |8| extending through a slot |82 in the carrier hub 11 andoperatively engaging a recs |88 in a sleeve valve 5|. It will beapparent that as the carrier 52 rotates at higherl speeds, the resultantcentrifugal force acting upon the weights |18 will cause the sleevevalve 5| to move to the lett against the resistance of the primary andsecondary springs v51 and 58. The amplitude of this movement isdependent upon the rotational speed of the carrier and the respectiveresistances of the springs; and it will be observed that as thismovement oi the sleeve valve takes place, successive ports are broughtinto alignment with or closed oil' from cooperating ports in the hub 11and the clutch sleeve 49 to establish diflerir hydraulic circuits.

'Ihe exact function and operation oi' this par'- ticular mechanism canbest be seen in Figures 3 to 9 and l1 to 16, inclusive. Figures 3,5, and8 show the longitudinal arrangement of a representative portion of thecontrol apparatus under various speed and directional conditions, andmost oi the constituent elements have been identiiied and described inrelation to Figure l. f Figures l'l to 16 show the successive transversearrangements under similar conditions.' Generally. it may be noted thatthe clutch carrier hub 11,v

. i'or each pair o1' cylinders. midway between the Thus, the hub 11 hasa secolltl` ananas' oil to waste to the interior oi'the housing andthence to the sump III.

The sleeve valve 8| also has a second speed conduit |82 and a thirdspeed conduit |88 for each cylinder, 'arranged in the same axial planesas the conduits |84 and |88r which are, oi' course.` the same yaxialplanes as those o! each of the individual cylinders 19. In addition. alongitudinally extending oil groove |84 (shown inidotted` line in Figure3) is located on'the outer circumference oi' the sleeve valve 5|, midwaybetween each of the pairs oli-conduits. These are thus.

. with the bleed |14 in the accelerating valve |84 other conduitssupplying each of the cylinders in the respective pair and' leading fromthe bore o! previously described. The oriilce permits oil to ow behindthe sleeve valve as it moves towards the left, and keeps the third speedclutch engaged during merely minor speed variations. However, this mustbe overruled at the lowest speeds and for idling when the vacceleratoris released compietely and this is accomplished vby the bleed |14 whichpermits a drop in third speed oil pressure at the pump and in thechamber 284 behind the sleeve valve 5|, so that the sleeve valve 5| isforced tothe right by the operation of the springs 51 and 58 and the oilis then forced out of the chamber 284 through the conduit 288 past thebushing 2|8 which has a slight clearance (see Figure) The sleeve valve5| has an auxiliary outer sleeve |81 and a somewhat longer auxiliaryinner sleeve |88.

The latter restricts. the travel of the sleeve valve `forwardly whilethe outer sleeve |91, about mldway of the travel ofthe sleeve valve,bears against the retaining ring |88 of the secondary spring 58. Furthermovement of the sleeve valve 5| Iori' wardly is then resisted by bothsprings 51 andil.V

The clutch sleeve 49 also has second and third speed conduits 28| and282 axially aligned with the centers of each of the cylinders andcorresponding to the axial planes of the similar conduitsin the-sleevevalve 5| and hub 11. Again,

i speed clutches.

Reference is now made to Figures 3 through 9 and 1l through 16 asindicating, rst, the relative positions of the control apparatus; and,second, in a diagrammatic fashion, the power ilow through thetransmission from the engine `to the driven shaft under each conditionot operation.

FIRST SPEED Figures 3, 4, 11, 13 and 15 In Figure 3, the controlmechanism is shown at ilrst speed operation during which therotational'speed of the clutch carrier is low enough so that thecentrifugal weights |18 are not perceptibly displaced. As a consequence,the sleeve valve 5| remains substantially ln'its most rearward position.Under these conditions, neither the second or third speed clutches 48 or58 is yoperated, as the auxiliary-inner sleeve |98 prevents the passageof oil from the supply 59 through the conduits 28| (Figure 11); and thesleeve valve 5|, proper, blocks the passage of oil and vis rotatedaccordingly.

from the suppiy sn through thev oonduits zu: ,(Fiul'e 13). Moreover, oilin the cylinders 19 is freeto drain to the sump through the conduits |94which are not completely covered by the outer auxiliary sleeve |91(Figure 1l); and from cylin- `ting the torque to the driven shaft Ilthrough the sun pinion |03 engaging the corresponding planet pinion |08.'I'he forward speed brake ||9 is engaged through the manual controlactivating vthe overrunning clutch IIB to prevent reverse rotation ofthe planet carrier 99. 'I'he clutch carrier 52 `has its sun piniony I|l|constantly meshed with the corresponding planet pinion |04 However, bothclutches 49 and 6|) are disengaged and there is `no reaction. Underthese conditions, the maximum engine torque is transmitted to the drivenshaft inthe forward'direction and at the lowest speed ratio. REVERSEFigures a, 5, 11, 13 and 15 In the reverse operation, the condition ofthe control mechanism is precisely the same as that for first speedforward. However, while--as described below-rst speed operationautomatically changes to second speed operation, as the vehicle speedincreases through the hydraulic control; increased reverse speeds haveno such eii'ectfas the pump which furnishes the oil` to operate thehydraulic control is only operated when the vehicle moves forwardly. Itwill be recalled that manualoperation is necessary to select forward or`reverse speeds throughthe medium of selective brake engagement. Thus,in Figure 5, the drive is again taken from the crank- `shaft l'throughthe impeller I9 and by reaction on the runner 23 and thence through theoverrunning clutch 25 to the main shaft 29. As before. the sun pinion|92 drives the planet pinion |09v and, of course, the other planetpinions |04 and |09 are also rotated. However, the forward speed brakeI9 is now released so that the car-- `rier y99 is free of the restraintof theloverrunning SECOND SPEED Figures 6, 7. 12,13 and It wasy notedunder the description of erst speed operation, that the clutch carrier52 was rotated, but that its rotational speed was not sufllcient tocause radial displacement of the centrifugal weights |19 and consequentaxial displacement of the sleeve valve il against the resistance oi' theprimary spring 51. However, as the rotational speed increases, theweights move outwardly and the sleeve valve 5| is projected axiallyforward uxrtil it reaches the position shown in Figure 6. The exactspeed at which this'` occursis. of, course, a function of the weight`and the spring loading. When this position is reached, the seco adspeed clutch 4|) is engaged by oil flowing from second clutch supply 59through the conduits 20|, |92 and IBI to the second speed clutchcylinders` 19 (Figure 12) and projecting the pistons 98 foi 'wardlyoperating the ring 99 to engage the disci; 41 and 99. The third speedclutch 50 remain l inactive and the control mechanism is funct` onallyunchanged from that shown in` Figure; 3, 13 and 15.

In operation, :s shown in Figure 7, this locks crankshaft I8, tl leimpeller housing I9 and the associated drum I6 directly to the clutchcarrier 52. This, in tur: i, drives its sun pinion Il and the tripleplane ary pinion through |04. I'he drive is again ;aken off through theplanet pinion |08 and is sun pinion |03 on the driven shaft 64. Theiorward speed brake H9 is still engaged prevent ng the reverse rotationof the planet carrier `|19 so that forward rotation at an intermediatespe( :d ratio is imparted to the driven yshaft. Themai n. driving shaft29, is, of course, rotated through '.he pinions |02 and |05, but theoverrunning cluti :h 25 disassociates the runner 23 and permits it fre erotation. The drive is entirely mechanical and whe fluid coupling isinoperative.

'L'HIRD SPEED `Figui 8.9.8, 9, 1214 and 15 As the rotation al speed ofthe clutch carrier 52 increases, the cer trifugal weights |18' willundergo further radial displacement and, in consequence, the sleevevalve 5| will be projected further toward the left against the combinedresistance of the jxrimary and secondary springs 51 and 58 untilltoccupies the position shown in Figure 8. The use of the separatesprings permits a shan: er differentiation between the two speed rangesand gives a sharper action. As a matter of illusi ration, the primarySpring 51 is l `demoted through its mitm range'by a load or about 10pound: andthe secondary spring l! Employing these ratios, a properbalance is obtained between tl .e third and second speed ranges andasuiliciently positive action is obtained either with increasing Jrdecreasing speeds with and without sacrifice of smoothness, Whilemulticoil springs are shown. it is quite possible-and under some condtions advantageous-to use single coil springs n their place. These loadup much more quicrly as theyapproach ultimate deflection and gi re aneven sharper division between the second and third speed ranges.

Under these omditions, oil under pressure is still supplied to 1hesecond speed clutch 4|) precisely in the mar ner described withreference to second speed ope ration, the flared ends |95 and 203permitting `the continued ilow of oil despite l are sumciently displacedfrom the conduit III that oil from the second speed clutch lll cannotflow out through themnor can oil be admitted from the third sr eedside.. The balance between the discharge raes of thebleed |14 inthe ac-1l celerating valve and the oriiice ISI normally keeps the ton in thirdspeed even when the speed momentarily falls somewhat below the usualoperating speed, since the oil through the orifice |95 preventsimmediate responsive movement of the sleeve valve Il. However, this isoverruled by the further loss in third speed clutch line pressure byleakage through the bleed I1! when the engine approaches idlingconditions. The precise capacities of these orifices is a matter ofexperiment to obtain the reqmaite balance, but they are important inmamv taining the requisite smoothness of operation unall conditions.

Referring now to Figure 9, power is transmitted as shown directly fromthe crankshaft AI6 through the impeller housing IB and the drum not dragthe hydraulic coupling, as'the overrun-A ning clutch 25 permits its freeoperation. The

' drive is entirely` mechanical and the fluid coupling is not utilized.As before. the forward speed brake I'I l is energized. but this has noeilect since there is no reaction to overcome while the planet carrieris locked with respect to the triple planet gear. 'Ihe torque is nowtransmitted at engine speed in the forward sense.

NEUTRAL Figures 1, 2 and 2A Fbr neutral, both brakes IIB and arereleased. No specific4 drawing indicates this condition, but it will beunderstood that the neutral notch l voi! the `ratchet |38 is thenengaged by the selector |42 and the cams l and |35 have displaced thearms "Gand Ill to the right and left, respectively. Under theseconditions, theoretically, no torque is applied to the shaft El.However, as in many trns of this'vtype utilizing a iiuidcoupling. isactually a tendency to creepwhich can kbe very troublesome unless properprovision is made for it. Usually, the emergency brake of the vehicle isrelied upon under such circumstances; but this requires speciilcoperation by the driver and,

hence. is'not entirely safe. 'Ihis may be prevented automatically by theanticreep brake. showninliigures 1and2andeffectvebetween the clutchcarrier 52 and the planet carrier I. 'I fhis includes a brake band 2l!having an inner braking surface 206 co-operating with a comzpleruentarysurface 201 on the planet carrier I9: 'The band 205 is cut away at 2M toincrease its exibility, leaving segments 2l! which serve as additionalresponsive to centrifugal forces imposed by rotation of the carrier S2on which lcoupling obtaining during idling to impede relative rotationoi' the two carriers and prevent creep. However, at higher speeds.centrifugal foro e acting on the segments of the band 2li l2overcometheresistanceofthespring2l$,ths band 205 moves outwardly and thesurface 2li and 201 are disengaged. Normal relative operation of the twocarriers may then continue.

'The principal points to be noted in the operation of the device arethat both second and third speeds are accomplished mechanically-that is.without depending upon the hydraulic coupling. 0n the other hand, thetorque conversion in ilrst and reverse speeds is effected through thehydraulic coupling when smoothness of transition has particularimportance and where the efllciencyl is not of such great moment sincethe vehicle operates for only a short period of time in these speedranges. Moreover, the constructionis such that the iluid couplingpresents no drag on the operation of the device in second and thirdspeeds. Another point is that by having individual sources of supply tothe second and third speed clutches, it is possible to maintainthesecond speed clutch in engagement even at speeds above the normalsecond speed range, when the third speed clutch is effective as well. Ithas been noted above that at higher speeds the centrifugal force, actingupon the oil behind the pistons by reason of the rotation of the clutchcarrier, keep both clutches engaged. Moreover, when it is desired toobtain immediate acceleration' beyond that afforded by third speedratio, even though the vehicle is then proceeding in third speed, thefact that the oil pressure is constantly maintained in the second speedclutch permits an immediate Atransition to that speed with a consequentincrease in torque to obtain the desired acceleration. Further, whilethe vehicle speed decreases, it is not necessary to re-engage the secondspeed clutch since it remains in engagement at all speeds above thoseobtaining for rst. A further point to be observed is that by cushioningthe operation of the sleeve valve, thetransition downwardly to idlingspeed is made more smoothly. Adequate automatic prevention of creep issecured Still another factor is that by locking out the reverse brakethrough hydraulic pressure, chance engagement of the manual control inthe reverse position is precluded so long as the vehicle is proceedingforwardly'.

It will be understood that the term fluid coupling" as used in thespecification and claims is to be interpreted as meaning a fluid powertransmitting device of the two element hydro-kinetic type utilized totransmit power between drive and driven members of the transmission.

Some changes may be made in the arrangement, construction.' andlcombination of the various parts of the improved device, withoutdeparting from the spirit of the invention and it is the intention tocover by the claims, such changes as may reasonably be included withinthe sco thereof.

The invention claimed is:

l. In a variable speed power transmission, in combination. a power shaftand a load shaft and a main shaft axially arranged, a fluid couplingcomprising a power receiving element fixed for rotation with said powershaft and a power delivery element having a one-way driving connectionwith said main shaft. a planetary gearing system including planet piniongears mounted on a planet carrier rotatably supported about the axis ofsaid shafts and respectively meshing sun gears, selectively operabletorque reaction means associated with said planet carrier forobstructing rotational movement of said planet carrier in one direction,an intermediate rotatable power transmitting vattacca on said loadshaft, manually operable means to secure said power transmitting memberagainst` rotation, first clutch means to fix said power transmittingmember for rotation with said power shaft, a second clutch, meansconnecting said second clutch to said power transmitting member, meansalso connecting said second clutch to said planet carrier, and means foroperating said second clutch means only concurrently with saidnrstclutch means.

2. In a variable speed power transmission, in combination, a power shaftand a main shaft and a load shaft axially arranged, a fluid couplingcomprising a power receiving element fixed for rotation with said powershaft and a power delivery element having a one-way driving connectionwith said main shaft, a planetary gearing system including planet piniongears mounted on a planet carrier rotatably supported about the axis ofsaid shafts and respectively meshing sun gears, selectively operabletorque reaction means associated with said planet carrier forobstructing rotational movement of said planet carrier in one direction.an intermediate` rotatable Power transmitting member including one ofsaid sun gears, a second sun gear on said main shaft, a third sun gearon said load shaft, manually operable means to secure said powertransmitting member against rotation, first clutch means to flx saidpower transmitting member for rotation with said power shaft, a secondclutch, means connecting said second clutch to said power transmittingmember, means also connecting said second clutch to said planet carrier,and means for operating said second clutch means only concurrently withsaid rst clutch means.

` 3. In a variable speed power transmission, `in combination, a powershaft and a main shaft and a load shaft axially arranged, a fluidcoupling comprising a power receiving element xed for rotation with saidpower shaft and a power delivery element having a one-way drivingconnection with said main shaft, a planetary gearing system includingplanet pinion gears mounted on a planet carrier rotatably supportedabout the axis of said shafts and respectively meshing sun gears,selectivelyoperable torque reaction means associated with said planetcarrier for obstructing rotation of said planet carrier in one directiononly, an intermediate rotatable power transmitting member including oneof said sun gears, a second sun gear on said main shaft, a third sungear on said load shaft, manually selectively operable manual means tosecure said power transmitting member against rotation or to operatesaid torque reaction means or to hold `both lsaid securing means andsaid reaction means inoperative, first clutch means to flx said powertransmitting member for rotation with said power shaft, a `secondclutch, means connecting said second clutch to 'said power transmittingmembermeans also connecting said second clutch to said planet carrier,and means for operating said second clutch means only concurrently withsaid first clutch means.

4. In a variable speed power transmission, in combination, a power shaftand a main shaft and a load shaft axially arranged, a fluid couplingcomprising a power receiving element fixed for rotation with said powershaft and a power delivery element having a one-way driving connectionwith said main shaft, a planetary gearing system including planet piniongears fixed for common rotation and moi nted on a planetcarrierrotatably supported aiout theaxis of said shaft `and respectivelymesi ing sun gears, selectively operable torqueL react lon meansassociated with said planet carrier fcr obstructing rotationiof` saidplanetcarrier in one direction only, an `intermediate rotatabl a powertransmitting member including one of s aid sun gears, a second sun gearon said main sha t, a third sun gear on said load shaft, manually coerable selective means effective to secure said pov er transmittingmember against rotation or to op( rate said torque reaction means ortohold both sa d securing means and said reaction means inopi rative,first clutch means carried on said pou er transmitting member to fixsaid power transmitting member for rotation with said power shaft secondclutch means mounted on said power tr: nsmitting member, meansconnecting said secoi id clutch to said planet carrier, means for opera,ing said second clutch means only concurrentl:r with said first clutchmeans. hydraulic actuatng means for said clutches, a valve controllingsaid hydraulic actuating means, a governor operating said valve toactuate said first clutch aboie a predetermined load shaft speed and toacti late both said clutches above a predetermined hi| :her load shaftspeed:

5. In a variable speed power transmission, in combination, a hc using,apower shaft and a main shaft and a load shaft axially arranged, a `fluidcoupling comprising a power receiving element fixed for rotation withsaid power shaft and a power delivery ell ment having a one-way drivingconnection with said` main shaft, a planetary gearing system in :ludingplanet pinion gears fixed for common rotation and mounted on a planetcarrier rotatably supported about the axis of said shafts and respel:tive `meshing sun gears, selectively operable tirque reactionmeanseffective between said hou iing and said planet carrier for obstructingrotati on of said planet carrier in one direction only, an intermediaterotatable power transmitting member including one of saidsun gears, asecond :un gear on said main shaft, a third sun gear on said load shaft,selectively operi able means on sa 'ld housing to secure said powertransmitting member against rotation, externally ond clutch to saidplanet carrier, said second clutch means be: ng operable onlyconcurrently with said first ch t-ch means, hydraulic actuating meansfor said c? utches, a valve controlling said hydraulic actuati ig means,a governor operating.

said valve to enge ge said first clutch'above a predetermined loadrlhaftspeed and to engage said second clutch abi: ve a predetermined higherload shaft speed, and externally operable means to `overrule saidgoiernor to` restrain operation of said clutch above said predeterminedhigher vload shaft speed. i y

6. In a variable speed power transmission, in combination, a hc usng, apower shaftand a main shaft and a` load shaft axially arranged in saidhousing, a fluid coupling comprisinga power receiving elemen; xed forrotation `with said power shaft and a. power delivery element having aone-way'driving connection with said main amasar shaft, a planetarygearing system including triple planet pinion gears xed for commonrotation and mounted on a planet carrier rotatably supported about theaxis of said shaft and respectively meshing sun gears, selectivelyoperable torque reaction means effective between said housing and saidplanet carrier for obstructing rotation of said planet carrier in onedirection only, an intermediate rotatable power` transmitting memberincluding one of said sun gears, a second sun gear on said main shaft, athird sun gear on said load shaft, means on said housing to secure saidpower transmitting member against rotation, externally controllableselectively operable means effective to activate said torque reactionmeans or said power transmiting member securing means or to render bothsaid last-named means inoperative, first clutch means mounted on saidpower transmitting member and selectively operable to fix said powertransmitting member for rotation with said power shaft and said powerreceiving element, a second clutch, means connecting said second clutchto said power transmitting member, means also connecting said secondclutch to said planet carrier, said second clutch means being operableonly concurrently with said first clutch means, hydraulic actuatingmeans for said clutches, a valve controlling said hydraulic actuatingmeans, a governor operating said valve to engage said rst clutch above apredetermined load shaft speed and to engage both said clutches above'apredetermined higher load shaft speed, externally operable means tooverrule said governor to restrain the operation of said second clutchabove said predetermined higher load shaft speed, and manually operablelwdraulic means for releasing said second clutch. '7. In a' variablespeed transmission, in combination, a housing, a power shaft, a loadshaft, a fluid coupling having one element fixed for rotation with saidpower shaft, a multiple planetary gearing system having one element xedfor rotation with said load shaft, a power transmitting memberinterposed between said fluid icoupling and said planetary gearingsystem and arranged for selective operation therewith, means renderingsaid member inoperative with respect to said fluid coupling and saidplanetary gearing ystem and to transmit torque in one direction throughsaidcoupllng and said planetary gearing system at one speed ratio, meanslocking said Lmember to said housing, means to lock said memjber to saidpower shaft and said planetary gearing to effect differential rotationthereof and rjtransmit torque at another speed ratio in said one'directlon, a clutch, means connecting said clutch to said powertransmitting member, means also lconnecting said clutch to a secondelementv of said planetary gearing system, means applying said clutch tolock said member to said power shaft and said planetary gearing systemto effect common rotation thereof and transmit torque at a third speedratio in said one direction, and

i means rendering said fluid coupling inoperative fwhile torque istransmitted at said last two speed Cil means rendering said memberinoperative with respect to said uid coupling and said planetary gearingsystem and to transmit torque in one direction through said coupling andsaid planetary gearlng'system at one speed ratio, means locking saidmember to said housing, means to lock said member to said power shaftand said planetary gearing and to effect differential rotation thereofand transmit torque at another speed ratio in said one direction, aclutch, means connecting said clutch to said power transmitting member,means also connecting said clutch to a second element of said planetarygearing system, means applying,r said clutch to lock said mem- `ber tosaid power shaft and said planetary gearing system and to effect commonrotation thereof and transmit torque at a third speed ratio in said onedirection, means rendering said fluid coupling inoperative While torqueis transmitted at said last two speed ratios, said member includingcontrol means automatically responsive to the rotational speed of saidmember to operate said last two locking means` 9. In a variable speedtransmission, in combination, a housing. a power shaft, a load shaft, afluid coupling having one element fixed for rotation with said powershaft, a multiple planetary gearing system having one element thereoffixed for rotation with said load shaft, a power transmitting memberinterposed between said fluid coupling and said planetary gearing systemand arranged for selective operation therewith,

`means rendering said member inoperative with respect to said fluidcoupling and said planetary gearing system and to transmit vtorque inone direction through said coupling and said planetary gearing system atone speed ratio, means locking said member to said' housing, means tolock said member to sa-id power shaft and said planetary gearing toeffect differential rotation thereof and to transmit torque at anotherspeed ratio in said onel direction, means to lock said member to saidpower shaft and said planetary A gearing system to effect'commonrotation thereof and transmit torque at a third speed ratio in saldil ione direction, means rendering" said fluid coupling inoperative whiletorque is transmitted at saidlast two speed ratios,rs'aid last twolocking means comprising hydraulically activated clutches car-2:;

ried on said member, conduits leading to said clutches, a series ofhydraulic valves in said conduits, a device on saidmember responsive tothe rotational speed thereof and effective to operate said valves, apump'driven by said load shaft to deliver fluid under pressure vto effectrespective operation of said clutches, and means limiting the operationof said valves to permit the application of one said clutch at apredetermined load shaft speed range and of both said clutches at ahigher predetermined load shaft speed range.

10. In a variable speed transmission, in combination, a housing, a sump,a power shaft, a load shaft, a fluid coupling having one element fixedltorque in one direction through said coupling and said planetary gearingsystem at one speed ratio.

amasar 7 l means locking said member to said housing, means to lock saidmember to saidpower shaft Y and said planetary gearing system to euectemerratio in said one direction, and meansrendering said fluid couplinginoperative while torque is transmitted at sald1ast two speed ratios.`

11. The structure of claim 10 which is further characterized in thatsaid last two locking means comprise clutches on said memberco-operating with said power shaft and the carrier of said planetarygearing system respectively, hydraulically activated operating cylindersfor said clutches, conduits leading to 'said cylinders, a series of`valves in said conduits controlling `the flow therethrough, a device onsaid carrier responsive to the rotational speed thereof controlling saidvalves, and a pump driven by said load shaft supplying activating fluidunder pressure to said conduits.

l2. The structure of claim l which is further characterized in that saidlast two locking means comprise clutches cio-operating with saidl powervshaft and the carrier of said planetary gearing system respectively,hydraulically activated operating cylinders for each of said clutches,conduits leading to said cylinders a series of valves in said conduitscontrolling the hydraulic flow therethrough, a device on said carrierresponsive to the rotational speed thereof `controlling said valves, apump driven by said load shaft supplylng activating fluid under pressureindependently to said conduits, and an accelerator controlled valveselectively operable to interrupt the flow ofsuch fluid to one of saidconduits.

` 13. The structure of claim which is further characterized in that saidlast two locking means comprise clutches on said member co-operatingwith said power shaft and the carrier of said planetary gearing systemrespectively, hydraulically activated operating cylinders for saidclutches, conduits leading to said cylinders, a slidable sleeve valveinterposed in said conduits controlling the flow therethrough, a deviceon said carrier responsive to the rotational speed thereof and e'ectiveto move said sleeve valve axially, a pump driven by said load shaftsupplying activating fluid under pressure independently to saidconduits, a first spring means resiliently resisting the movement ofsaid sleeve valve in response to said device through an initialpredetermined range, a second spring means resiliently resisting thefurther movement of said sleeve valve in response to said device througha second predetermined range, said sleeve valve being so arranged thatsaid conduits to one said clutch are opened at the end of said firstrange and that said conduits to the other said clutch are also opened atthe end of said second range.

14. The structure of claim 10 which is further characterized inthatlsaid last two locking means comprise clutches on said memberco-operating with said power shaft and the carrier of said planetarygearing system respectively, hydraulically activated operating cylindersfor said clutches, conduits leading to said cylinders, a slidable sleevevalve interposed in said conduits controlling the flow therethrough, adevice on 18 said carrier responsi ve to the rotational `speedthereofeective to m ove said sleeve valve axially, a pump driven by sal i loadshaft supplying activating fluid under prl issureindependently to saidconduits, a first sprin g means resiliently resistingv the axialmovement of said sleeve valve in response to said device from an initialposition in which said conduits s re closed to an intermediate positionin which l Lid is admitted to one said cylinder, a second sp1 lng meansresiliently resisting further axial mc vement of said sleeve valve fromsaidintermediate positionto ak final position in which fluid` i:admitted to the other said cylinder, said one cylinder beingcontinuously activated after said s eeve valve passes said intermediateposition. 0

l5. The'structure uf claim 10 which is further characterized m that said18st two mening means comprise clutches or said member co-operating withsaid power shift and the carrier of said planetary gearing systemrespectively, hydraulically activated opemting cylinders for each ofsaid clutches. condui ts leading to said cylinders.y

the axial movement of said sleeve valve in response to said devicl froman initial position in which said. conduits i yre closed to anintermediate position in which fluid is` admitted to one said cylinder,a second sp1 ling means resiliently resisting further axial mc vement ofsaid sleeve valve from said intermedia :e position to a final positionin which uid is adm ltted to the other said cylinder, said valve havin;passageways communicating kwith said conduil s as the rotational speedof said carrier decreases and said sleeve valve is returned to itsinitial position under the urging of said spring means andsimultaneously communicating with the sump to drain oil from saidcylinders.

16. The structure if claim 10 which is further characterized in tha1said last two locking means comprise clutches on said memberco-operating with said power shaft and the carrier of said planetarygearing system respectively, hydraulically activated operating cylindersfor each of said clutches, condui :s leading to said cylinders, a sleevevalve effective on axial movement'l to control the flow throug rl saidconduits, a device on said carrier respon: ive to the rotational speedthereof effective to move said sleeve valve axially. a pump driven bysaid load shaft supplying fluid under pressure independently to saidconduits, a first spring means resisting the axial movement of said slieve valve in response to said device from an initie l position in whichsaid conduits are closed to an intermediate position in which lfluid isadmi '.ted to one said cylinder, a second spring mean; increasinglyresisting further axial movemert `of said sleeve valve from saidintermediate plsition to a final position in which fluid is admiti ed tothe other said cylinder, said valve having liassageways communicatinginversely successivel I with said conduits, as the rotational speed ofsa yid carrier decreases and said sleeve valve is returx ,ed to itsinitial position under the urging of sa id spring means andsimultaneously communie ting with the sump to drain oil from saidcylinder 1'?. The structure of claim 10 which is further areas with saidpower shaft and the carrier or said planetary gearing systemrespectivek. hydrau lically activated operating cylinders for' saidclutches, conduits leading to said cylinders, a sleeve valve interposedin said conduits controlling the flow therethrough. a device on saidcarrier responsive to the rotational speed thereof adapted tomove saidsleeve valve axially as the speed increases. a pump driven by said loadshaft supplying fluid under pressure independently to said conduits, afirst spring means resiliently resisting the axial movement of saidsleeve valve in response to said device from an initial position inwhich said conduits are closed to an intermediate position in whichfluid is admitted to one said cylinder, a second spring meansresiliently resisting further axial movement of said sleeve valve fromsaid intermediate position to a nal position in which iluid is admittedto the other said cylinder, and hydraulic means initially resisting thereturn of said sleeve valve from said ilnal position when rotationalspeed of said carrier decreases.

18. A structure of claim l0 which is further characterized in that saidlast two locking means comprise clutches 'co-operating with said powershaft and the carrier of said planetary gearing system respectively,hydraulically activated operating cylinders for said clutches. conduitsleading to said cylinders. a sleeve valve interposed in said conduitsand eective to control the flow therethrough, a device on said carrierresponsive to the rotational speed thereof and'adapted to move saidsleeve valve into successive positions of co-operation with saidconduits. a pump driven by said load shaft supplying activatingiluidunder pressure independently to said conduits. a first spring meansresiliently resisting the movement of said sleeve valve in response toincreased speed of the carrier from an initial position in which saidconduits are closed to an intermediate 20 position in which iluid isadmitted to one said cylinder, a second spring means resilientlyresisting further movement of said sleeve valve from said intermediateposition to a nal position 1n which iluid is admitted to other. saidcylinder. and externally operated overriding means effective at saidpump to interrupt the now of fluid to the other saidcylinder.

19. In the structure of claim 10V which is fur- `ther characterized inthat said control means comprise a pump driven by said load shaft andsupplying activating iluid under pressure to operate certain oi.' saidvlocking means, and said locking means eiective between said member andsaid housing includes a cylinder supplied with iluid from said pump andeifective to restrain the engagement of said locking means so long assaid load shaft is operating in said one direction.

20. The structure of claim 10 which is further characterized in thatsaid planetary gearing system includes a planet carrier. a.centrifugally operated brake carried by said member and adapted toco-operate with said carrier to restrain relative rotation therebetweenat idlingv speeds and to be disengaged therefrom as the rotational speedof said carrier increases.

EUGENE J. FARKAS.

REFERENCES CITED The following references Iare of record in the ille ofthis patent:

UNITED STATES PATENTS

